excellent…
here is what I honestly would do…
confort the person face to face…no violence (yet)… give them the option of returning all the stuff they stole…
if they choose not to go to police, explain to them what happened the first time (no witnesses etc) then the attempted it again and this time you got their license plate number, make model etc…have the person who was there last night back your story up. Get the police on them. if this step fails, street justice is in order